Base detonating fuse



All@ 30, 1949 l.. K. LILJEGREN 2,480,149

BASE` DETONATING FUSE Filed May 22, 1945 2 Sheets-Sheet 1 Aug. 30, 1949.

Filed May 22, 1945 L. K. LlLJEG REN BASE DETONATING FUSE 2 Sheets-Sheet 2 gwumvfofa @M MWWMM Patented Aug. 30, 1949 s UNITED STATES PATENT OFFICE BASE DETONATING FUSE Lyle K. Liljegren, Alexandria, Va.

Application May 22, 1945, Serial No. 595,231

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0.. G. '757) .6 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to an improved construction of base detonating fuze for rotatably type projectiles which is armed during ilight by centrifugal force and which is detonated upon impact of the projectile with a target by the inertia force thus produced.

. More particularly, it is an aim of the invention to provide an improved construction of a projectile fuze including a novel construction of a plunger which is inertia actuated upon impact of the projectile with its target, and which supports a centrifugally actuated arming member which retains the fuze in a disarmed condition until after the fuze has left the bore of the weapon from which it is fired.

Still another aim of the invention is to provide a plunger having a novel means for supporting a primer which ignites an explosive train by means of which the bursting charge of the projectile is ultimately detonated.

Another object of the invention is to provide a fuze wherein the primer is carried by the plunger and movable relatively to a iixed striker or anvil.

A further object of the invention is to provide a fuze having novel means of simple construction to prevent casual release of detent members which function to retain the iuze in a safe or disarmed condition until the projectile, containing the fuze, is in flight.

Still another object of the invention is to provide a fuze having an indirect or circuitous flash passage between certain of the components of the powder train, which lead ultimately to the burster charge, for producing a delay ring of the booster charge after the fuze primer has been detonated.

Other objects and advantages of the invention will herein become more fully apparent from the following description of the drawings, which illustrates preferred embodiments thereof, and wherein:

a Figure 1 is a longitudinal, substantially central sectional view of the preferred form of the fuze and taken substantially along a plane as indicated by the line I-I of Figure 2;

Figure 2 is a view similar to Figure 1 but partly in side elevation, taken substantially along a plane as indicated by the line 2-2 of Figure 1;

vFigure 3 is a cross sectional View of the fuze taken substantially along a plane as indicated by the line 3-3 of Figure 1;

. Figure 4 is a cross sectional View of the fuze taken substantially along a plane as indicated by the line 4-4 of Figure 2;

Figure 5 is a View similar to Figure l ed form of the fuze; and

Figure 6 is a View similar to Figure 1 of another modied form of the fuze.

Referring more particularly to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, and referring particularly to Figures 1 to 4, l' designates generally the improved fuze in its entirety and which includes a fuze housing 8 having a longitudinally extending chamber 9 which opens outwardly of the inner end I0 thereof. A sleeve II is mounted in the open end of the chamber 9 and is secured therein by any suitable means such as a press fitting. Sleeve II is provided with an internally threaded outwardly opening bore portion I2 and has at its inner end a restricted opening I3 which opens into the bore portion I2 and into the inner end of the chamber 9. A head I4 is provided with a restricted, externally threaded neck I5 which extends into and is in threaded engagement with the threaded bore I2. A plurality of sealing gaskets or rings I6 are clamped between the head I4 and the inner end of the fuze housing 8. An anvil or striker I'I is provided with a base which is clamped between the annular shoulder I8, formed by the opening I3, and the free end of the neck I5. The striker Il is provided with a shank or stem I9 which extends axially through opening I3 and into the inner end of the chamber 9. The neck I5 is provided with a recess 20 containing a detonator 2| and the head I4 is recessed at 22 to receive a burster charge 23 which is retained within the recess 22 by a readily destructible closure 24. The neck I5 is provided with a flash passage 25 connecting the burster charge 23 to the detonator 2|.

A plunger 26 is mounted to slidably engage the inner end of the chamber 9 and is disposed for sliding movement lengthwise thereof toward and away from the striker element I9. The end of the plunger 26, which faces the striker element I 9, is provided with a recess 2l containing a primer 28 and a head 29 is anchored in the plunger 26 and is embedded in the primer 28, in alignment with striker element I9. As clearly illustrated in Figure 1, the recess 21 is of a sufiicient size and is correctly located to receive the striker element I9 when the plunger 26 is moved forwardly or toward the striker element. Plunger 26 is provided with a plurality of longitudinally extend` ing grooves 30 which extend from end to end,l

of a modi-v 3 thereof and which open outwardly of the periphery.

A detent, designated generally 3|, includes a base 32 which is disposed against the outer end of the plunger 26 and which is provided with a plurality of integral spring arms 33 which are normally disposed at acute angles to the base 32. One of the spring arms 33 extends lengthwise through each of the grooves 35. The spring arms 33 extend beyond the forward face of the plunger 26 and are provided with heads 34 which are fastened to the inner sides of the free ends of the arms 33 and which project inwardly therefrom. The heads 34 form centrifugalactuated weighted elements, for a purpose that will hereinafter be described. As best seen in Figure 1, the heads 34 are normally disposed between the surface 35 of the plunger 26 and the annular shoulder IS to prevent the plunger 28 from moving toward the striker element l5. As seen in Figure 1, the surface 35 is inclined outwardly and downwardly to provide an engagement with the heads 34 which will resist outward movement of the heads 34 and Iwhich will prevent saidheads from movingout of engagement with surface 35 except when swung in an arc having an axis approximately at the secured ends of the spring arms 33. Thus, the surface 35 functions to prevent casual displacement of the heads 34 and premature arming of the fuze "1. Between certain of the grooves 38, plunger 26 is provided with longitudinally extending recesses 36 which open outwardly of its forward face and in which are slidably mounted the inwardly opening cup-shaped plunger elements 31. Each of the recesses 35 contains an expansion coil spring 38 which extends into and bears against the plunger element 3'! thereof for urging said plunger elements outwardly of the recesses 36V and against the shoulder I8, to retain the plunger 26 in its retracted position, as seen in Figures 1 and 2.

The striker or anvil Ii, between its base and its striker element i9, is provided with a tapered neck portion containing a plurality of downwardly converging flash passages 38 which communicate with the opening I3 at their rear ends and with the recess 25, containing the detonator 2 I, at their forward ends.

Assuming the fuze l to be mounted in the base of a projectile, not shown, the fuze parts will lbe in their safe or disarmed positions, illustrated in Figures l and 2, prior to the time that the projectile is iired fromv a weapon and while it is-moving through the weapon barrel and for a short time thereafter. While thus disposed, the fuze T is safel and therefore renders the projectile, in

which it is contained, bore safe. No manual operation is necessary to arm or prepare the fuze for arming prior to the fuze being fired with its projectile, so that there is no danger of dude resul'ting due to the oversight of a member of the gun crew failing to arm or set the fuze for arming, prior to firing of the projectile. After the projectile, containing the fuze l, has been fired and when it has reached substantially its maximum speed of rotation, the weighted heads 34 will be swung outwardly by centrifugal force against the spring action of the arms v33 so that said heads willv be in alignment with the grooves '30, which are wider than the width or diameter of the heads 34, as seen in Figure 2. With the heads '34, thus disposed, the fuze 'i is armed and ready tofunction and the plunger '26 is held in its retracted position by the spring biased plunger elements 3T so that deceleration of the projectile will not detonate the fuze. Upon impact of the projectile containing the fuze 'I with a target, the plunger 26 will be driven forward by inertia against the resistance of the springs 38 and in so moving, the heads 34 will be received in the grooves 30 and the striker element I9 will be received in the recess 2'I. vStriker element I9 will thus be caused to strike the primer 28 which will be compressed thereby between the striker element I9 and the head 29 to detonate primer 28. The flash from primer 28 will pass through opening I3 and the converging ash passages 3!! to the detonator 2l. The hash from the ignited detonator 2I will detonate the booster charge 23 which will in turn detonate the booster charge of the projectile, not shown. The converging shape of the flash passages 38v produce a slight delay in conveying the flash from the primer 28 to the detonator 2 I, which is advantageous in order that the projectile can embed itself in its target before 4its burster charge is detonated'.

Figure 5 illustrates a slightly modified form of fuze, designated generally 46, having a housing 3, corresponding to the housing of the fuze 'I and containing a cavity 9 in the open end of Ywhich is mounted a sleeve 4I. Sleeve 4I is provided with a recess including a forwardly opening inwardly threaded portion 42 anda rear portion 43 con'- taining a primer holder 44 in which is mounted a primer 45. The inner end of the sleeve 4I is provided with a restricted opening 46 which communicates with the primer 45 and which forms an annular shoulder 41, surroundingthe opening 46. A head 48 is provided with a restricted threaded neck 48 which extends into and threadedlyV engages the threaded portion 42. Sleeve 4I may be secured in the chamber 9 in the same manner as the sleeve il, and the joint between thehousing 8 and the head 48 is sealed by gaskets I6, as inthe fuze '1. The neck'48 is provided with an enlarged recess 55 at its rear end containinga de tonating charge 5I and a more restricted recess 52A containing a second detonating charge 53. The head 48 has a recess 54 containing a booster charge 55, which is separated from the detonator 53 by a readily destructible partition 55. The booster charge 55 is contained in the recess 54 by a readily frangible closure 57. The holder 44 and a portion of the detonator 5I are provided with communicating bores forming a ash passage 58 between the primer 45 and the initial detonator5l.

The inner end of the chamber 9 contains a plunger 59 which is disposed for sliding movement lengthwise of the housing 8 and which is provided with a plurality of longitudinally extending grooves 68 which open radially of the plunger 59 and which lextend the length thereof, and the'- beds of which grooves G5 converge toward the forward end of the plunger 58. The plunger 59' is provided with a detent 3l, corresponding ln construction and operation to the detent of the fuze I and differing therefrom only in slight variations cf size to adapt it to plunger 59. The plunger 55 is providedV with a forwardly projecting striker 6i' which is axially disposed and aligned with the opening 46 and which is located between the weighted heads 34. The weighted heads 34 normally bear against the outwardly and downwardly inclined surface 62 of the plunger 59'and are disposed to engage the shoulder 47 to prevent the striker 6I from moving into the opening 46, until the heads 34are moved outwardly by centrifugal Vforce to arm the fuze 40. Plunger 58 is provided with springs 38. andfplu.ng ers-31, one of a-pluralityof'sets of which is shown in Figure 5, for holding the plunger 59 in a retracted position, after the detent 3| has moved to its fuze arming position.

rom the foregoing, it will be apparent that the fuze 40 is armed in the same manner as the fuze 1, during flight of the projectile in which it is contained, and upon impact of the projectile with a target, plunger 58 is moved forward by inertia with its groove 60 receiving the heads 34, thereby causing its striker or firing pin 6| to engage or detonate the primer` 45. The flash from the primer 45 passes through flash passage 58 to detonate the initial detonator 5I, the flash from which ignites detonator 53. Detonator 53 in turn ignites the booster charge 55 which in turn sets off the burster charge of the projectile, containing the fuze 49.

In Figure 6 another variation of the fuze, designated generally 63, is illustrated, having a slightly modified form of housing 64 which is reduced in length and which contains a shortened chamber 65. A coupling member 66 is provided with a neck 66' which extends into the forward end of the chamber 65 and which is suitably secured to the housing 64. Coupling member 66 is provided with a forwardly opening recess 61 containing a sleeve 68 having a forwardly opening internally threaded cavity 59. A head 10 is provided with a threaded neck 1l which engages the cavity B9 and which is recessed to contain a detonator 12. The head 10 is provided with a recess 13 containing a booster charge 14. Said recess 13 is closed by a frangible closure 15. The sleeve 68 is provided with a very restricted passage 16 which connects the chamber 61 with the detonator 12,

and the neck 61 is provided with flash passages 'I1 which communicate with the rear end of the chamber 65 and the chamber 61. Neck 66 is provided with an integral anvil or striker 18 which projects axially into the chamber 65.

Chamber 65 slidably mounts a plunger 19 having a centrally disposed forwardly opening recess 80 into which the rear end of the striker 18 extends and in the rear end of which is contained a primer 8|, which is spaced from the striker 18. Plunger 19 is provided with longitudinally extending grooves 82 for receiving the spring arms of a detent 3| which is carried by the plunger 19, and which corresponds to the detents of the fuzes 1 and 40.

The fuze 63 is armed during flight in the same manner as the fuzes 1 and 49, and after arming, the plunger 19 is held in a retracted position by plungers 31 and springs 38, one of which plungers 31 is shown in Figure 6. Upon impact of the projectile, containing the fuze 63, plunger 19 is driven forwardly by inertia causing the primer 8i to strike the anvil 18 and be detonated thereby. The flash from the primer 8l is conveyed through passages 11, the inner part of cavity 61 and through the passage to the detonator 12. The flash from the ignited detonator 12 is conveyed by means of a passage 82, in the neck 1l, to the booster charge 14 which upon being detonated sets off the projectile charge, not shown.

Obviously, various other modifications and changes in the construction and arrangement of the parts forming the fuze are likewise contemplated and may be resorted to without departing from the spirit and scope of the invention, as hereinafter defined by the appended claims.

I claim:

1. A base detonating centrifugally armed projectile fuze comprising a housing having a forwardly opening chamber, an internally threaded sleeve disposed in the forward end of the chamber, a head having a threaded neck extending into and threadedly engaging the sleeve, said neck having a chamber containing a detonator, an anvil disposed in the sleeve and extending into the inner end of the housing chamber, said head being recessed to contain a booster, a flash passage connecting the booster and detonator, a. plunger slidably mounted in the outer end of the housing chamber for movement toward the anvil, said plunger having an inwardly opening recess to receive the anvil when the plunger is moved forward by inertia, a primer in said plunger recess to be engaged by the anvil, a flash passage in the anvil for conveying the primer flash to the detonator, and a centrifugally actuated detent carried by the plunger and normally disposed between portions of the plunger and sleeve to retain the fuze in a. safe or disarmed condition, said detent being movable to an inoperative position, upon rotation, for arming the fuze.

2. A fuze as in claim 1, said plunger having longitudinally disposed grooves, said detent including spring arms extending through said grooves and therebeyond, and heads mounted on the free ends of the arms and extending inwardly therefrom and being disposed between surfaces of the plunger and sleeve, said heads being retractable, by centrifugal force, into alignment with the grooves to arm the fuze.

3. A fuze as in claim 1, the flash passage, formed in the anvil, being disposed to provide an indirect passage between the primer and detonate to produce a delay action in the ignition of the detonator,

4. A fuze as in claim 1, and a head carried by the plunger and embedded in the primer, said primer head being in alignment with the anvil.

5. A fuze as in claim 1, and spring pressed means slidably mounted in the plunger and extending therefrom and engaging the sleeve for yieldably retaining the plunger in a retracted position.

6. A fuze as in claim 1, the surface of the plunger, disposed to engage the detent to prevent detonation of the fuze, being inclined outwardly and downwardly to resist casual movement of the detent to a fuze arming position.

LYLE K. LILJEGREN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 822,289 Merriam June 5, 1906 999,268 Sohlman Aug. 1, 1911 1,145,937 Stout July 13, 1915 1,311,793 Driggs July 29, 1919 1,440,191 Wennerstrom Dec. 26, 1922 2,014,401 Teitscheid Sept. 1'1, 1935 FOREIGN PATENTS Number Country Date 28,306 Great Britain 1908 426,296 France Apr. 29, 1911 

